The present invention is directed to a electrical junction box commonly found in residential construction. More precisely, the present invention is directed to an electrical junction box that easily connects with ROMEX® and like sheathed electrical cable and in certain application, can slide along the electrical cables.
ROMEX® is the brand name for a type of plastic insulated wire commonly supplied by WesBell Electronics, Inc., Merrimack, N.H., USA. It is also know in the trade as non-metallic sheath or NM cable, and has two or three insulated wires plus a bare ground wire all wrapped together in a plastic sheathing. It is primarily used for indoor wiring in residences and commercial buildings to power appliances, ceiling fans, lights, AC sockets or outlets, switches, etc. The electrical cable is run through with or without conduits along the interior of walls or ceilings of a home, and is available in many wire sizes depending on application and building electrical codes.
Armored cables hold conductor wires inside a flexible steel or aluminum sheath and are known as BX or Armored Cable (AC). Armored cables with the metallic sheath provides more protection for the encased electrical conductors that non-metallic sheath cables.
In residential wiring, an electrical junction box or J-box is used as a terminus to ROMEX®, BX, and like electrical cables. The terminus is typically the location for a light, AC outlet, light switch, etc. Conventional junction boxes is a metal, plastic, or ceramic box where electrical cables pass into the box and the exposed electrical conductors contained in the cables are wired to terminal strips to complete and join electrical circuits. Somehow, the cable or conduit must be attached to the junction box.
Typically, the ROMEX® cable, BX cable, or flexible metal conduit is attached to an electrical junction box by use of a collar at the end of the cable or conduit. The collar affixes the plastic sheathed cable or metal conduit to a knock-out opening in a wall of the junction box housing, wherein the tubular-shape collar clamps to the wall with a threaded flange, a radiator hose style clamp, radial barbs, or pop-open wings similar to a toggle bolt that hold the collar to the surrounding wall. With the conduit or sheath affixed to the wall, the exposed conductor wires pass through the center opening of the collar and into the interior of the junction box where the electrical connections are made. Other structures such as fingers and inserts are used to grip, wedge, or otherwise affix the metal conduit or sheathed cable to the junction box.
A junction box is also located next to the can of a recessed lighting fixture. Non-metallic and metallic sheathed cables and conduits pass into the junction box and out from the junction box to the can to power the lamp inside the can.